Following the beat of cardiac potentials

A means to monitor the characteristics of the action potential can help clinicians determine if the heart is in an ischemic state, a condition in which the blood supply to the heart is obstructed. The precise delineation of the ischemic border zone may be important for identifying where to best deliver a therapeutic intervention (i.e., pharmacological agent, growth factor, gene therapy, or the delivery of stem cells). It may also be possible to observe shift in the baseline measurement of the resting membrane potential (phase four) that is independent of baseline wander or other artifacts. Some of these changes can also be observed in the body surface electrogram, the EGG. For example, ischemic phenomenon may be observed with surface EGG recordings in which the S-T segment may be elevated during ischemic conditions. However, the information gathered from the action potential recording yields more information than a 12-lead EGG exercise stress test, such as the precise location of ischemic event and its border zones